Top feeding mechanism for blind stitch sewing machines



R. S. KELSO Aug. 3, 1937.

TOP' FEEDING MECHANISM FOR BLIND STITCH SEWING MACHINES Filed Nov. 6, 1936 2 Sheets-Sheet 1 gmcmIom I I I I I I I III whiff Ouoww R. s. KELSO ,7

TOP FEEDING MECHANISM FOR BLIND STITCH SEWING MACHINES Aug. 3, 193 7.

2 Sheets- Sheet 2 Filed Nov. 6, 1956 women Patented Aug. 3, 1937 PATENT OFFICE TOP FEEDING MECHANISM FOR" BLIND STITCH SEWING MACHINES Ralph S. Kels'o, St. Louis, Mo., assignor to Lewis InvisibleStitch Machine Company, St. Louis, 'Mo., a corporation of Maine Application November 6, 1936, Serial No. 109,595

4 Claims.

This invention relates to new and useful improvements in top feeding'mechanism for blind stitch sewing machines.

Among the several objects of the invention are to provide a l-motion top feed mechanism housed within a forwardly extending stitching arm of a blind stitch sewing machine; to provide means for varying the feed stroke of the feed dog; and to provide such a mechanism which is extremely simple in construction and durable in operation.

With these and other objects in view which will more fully appear, the nature of the invention will be more clearly understood by following the description, the appended claims, and the several views illustrated inthe accompanying drawings.

In the drawings:

Figure l is a side elevation of a stitching arm showing the application of my invention,

Figure 2 is a bottom plan View thereof,

Figure 3 is a partial rear elevation thereof, the frame arm being shown in section,

Figure 4 is a detail elevation of the feeding mechanism, the view showing particularly the means for imparting up and down movements to 25 the feed dog, and

Figure 5 is a detail elevation showing particularly the means for imparting the backward and forward movements to the feed dog.

Like reference numerals designate correspond- 30 ing parts throughout the several figures of the drawings.

The sewing machine frame A to which my invention has been applied, includes a forwardly extending hollow stitching arm 5 having a horizon- 35 tel presser foot 5 rigidly secured to the free end thereof and provided with a longitudinal opening 'i. Journaled in the main frame and projecting transversely across the arm 5 at the end thereof opposite the foot 5, is a main or drive shaft is. Journaled in the arm 5 and extending longitudinally thereof is an oscillatory needle shaft 9 which is driven from the main shaft by a connection indicated generally at Ill. The needle shaft is disposed above the foot and fixed to 45 the forward end thereof is a needle arm H carrying a curved needle l2, the needle thus being reciprocated across the slot 1 in the foot 6. Any suitable means (not shown) may be provided for projecting nodes of fabrics upwardly through the 50 slot 7 into needle penetrating position. i

In order to feed the fabrics up to and past the needle, I have provided a 4-motion top feeding mechanism within the frame arm 5. This mechanism includes a feed dog l3 having a front feed 55 section I4 and a rearwardly spaced feed section 15, said sections being connected by a longitudinally extending bridge 16 forming a resultant opening ll thereunder. This feed dog I3 is attached to a feed bar is by screws l9. The feed sections operate in the opening I of the presser foot and against the usual upwardly spring pressed work clamp, the front section l4 being located in front of the needle path and the rear {section it in rearofsaid path. The feed bar l8 is raisedand' lowered by a train of mechanism from the main shaft 8, and is moved back and forth by a train of mechanism operated from said "main shaft. A bell crank lever 20 is pivoted at its angle as at 2i to the forwardly extending arm 5 of the frame. This bell crank lever includes a forwardly extending :arml22 and a downwardly extending arm 23. A link 24 is pivotally connected at its upper end as at 25 to the arm 22 and at its lower end as at 25 to the feed bar I8. The rear end of the feed bar is provided with an inclined open ended slot 23 which has sliding connection on a bearing pin 28 fixed to the forwardly extending frame arm 5. A pitman 29 is pivotally connected at its forward end as at 30 to the depending arm 23 of the bell crank lever 20 and the rear end of this pitman is connected with an eccentric 3i fixed on the main shaft 8. It will thus be seen that upon rotation of the main shaft, the eccentric 3i will rock the bell crank lever 20 which, through the medium of the link 25, will raise and lower the feed bar I 8. In order to move the feed bar back and forth, I have provided a slotted segment 32 which is pivoted at its upper end as at 33 to the forwardly extending frame arm 5. at its forward end as at 35 to the feed bar It and the rear end of this link is adjustably connected to the slotted segment 32 by a clamping bolt 36, the slot of the segment being arcuate and having for its center the pivot 35. The slotted segment 32 is pivotally connected as at 37 to a sleeve 38 which surrounds an eccentric 39 fixed on the main shaft 8. Thus upon rotation of the main shaft 8, the eccentric 39 will impart swinging movements to the slotted segment 32 and this segment through the medium of the link 34 will impart back and forth movements to-the feed bar I8. By adjusting the clamping bolt 36 lengthwise of the slotted segment 32 the length of feed travel imparted to the feed dog l3 may be readily varied.

It is of course to be understood that the details of structure and arrangement of parts may be variously changed and modified without de- A driving link 34 is pivotally connected tion with a hollow frame arm, of a rotary shaft extending across one endthereof, a feed bar extending longitudinally within the arm, a feed dogfixed to the end of the bar opposite the shaft, the inner'end of the bar'having a sliding pivotal connection with the frame arm, means for imparting up and down movements to the' feed bar including an eccentric fixed to said shaft, and separate means for imparting ,bac'kward'and forward movements to the feed bar including an eccentric fixed to said shaft. 7 I V 2. In a top feeding mechanism, the combina-; tion with a hollow frame arm, of a rotary shaft extending across one end thereof, a feed bar ex tending longitudinally within the arm, a feed dog fixed to theend of the 'bar opposite the shaft, theinner end of the bar having a sliding pivotal connection with the frame arm, means for imparting up and down movements to the feed bar comprising abell crank lever located intermediate the ends of'the feed bar and fulcrumed ion-,theframe arm above the feed bar, said lever including horizontal and vertical arms, .a supporting link connecting the horizontal arm and the feed bar, an eccentric fixed to the shaft,

and a pitman connecting the eccentric and the vertical arm of the bell crank lever, and sepa- 7 rate means for imparting backward and forward movements-to the feed bar including an eccentric fixed to saidshaft.

3. 'In a top feeding mechanism, the combination with a hollow frame arm, of a rotary shaft extending across one end thereof, a feed bar extending longitudinally within the arm, a feed dog fixed tothe. end of the bar opposite the shaft,

the inner end of the bar having a sliding pivotal connection with the frame arm, means for imparting up and down movements to the feed bar including an eccentric fixed to said shaft, and 7 separate means for imparting backward and for- -a driving connection betweenrthe eccentric and the segment, and a link pivotally connected at one end to the feed 'bar and having an adjustable 1 connection at its other end with said segment. ,4. Inc, top feeding mechanism, the combination with a hollow frame arm, of a rotary shaft extendingacross one end thereof, a feed barextending longitudinally within the arm, a feed dog fixed to the end of the bar opposite the shaft,

the inner'end of the bar having a sliding pivotal connection with the frame arm, means for imparting up and down movementsrto the feed bar comprising a bell cranklever located intermediate the ends of the feed bar, and fulcrumed on the frame arm above the feed bar, said lever '7 including horizontal and vertical arms, a sup; porting link connecting the horizontal arm and the feed bar, an eccentric fixed to the shaft, and a pitman connecting the eccentric and the vertical arm of the bell crank lever, and separate means for imparting backward and forward movements to the feed bar comprising an arcuate segment located intermediate the shaft and the feed bar and pivoted at its upper end to the frame arm, an eccentric fixed to the shaft, a driving connection between the eccentric. and the segment, and a link pivotally connected at one end to the feed bar and having an adjustable connection at its other end with said segment.

RALPH S. KELSO. 

